Lets Get Small

I’ve been slowly working on this microcontroller board (very slowly) for a while. I’m using PCB123 and some new, very small components to put it together. I’m amazed at the changes that have happened recently in this industry. Change has been a constant in this industry since it’s been around, but it only seems to be accelerating. Or at least, it’s taken a big jump just recently.

I’ve made size an important constraint so I picked a low drop out MCP1726 regulator instead of the venerable LM7805 or equivalent. In the old days, if size was a concern, I’d skip the TO-220 package and instead use something in a TO-92 package. But that would limit me to around 150ma, and it's a thru-hole part. That’s fine if it’s only the microcontroller, but I want to drive a bunch of LEDs, and I2C bus and some other logic circuits.

The old TO-220 package was about 10mm X 20mm plus the area needed for a heat sink to deliver a full amp. What amazes me is that this new part comes in an 8-lead DFN (same thing as a QFN –Quad Flatpack No leads - but with leads on two sides instead of four). It’s 3mm X 3mm and, with proper PCB design, can supply the same 1-Amp that the TO-220 packaged part could deliver with something like 50 times the surface area, not even including the heat sink.